LiquidCrystal-Display blue 1602 Arduino Nano

I recently bought several “Smart Electronics LCD Module Display Monitor 1602 5V Blue” for building a wifi alarm clock. It uses the very common Hitachi HD44780 driver. To verify if they are working I followed this well described tutorial on arduino.cc and used a arduino nano for that. Removing the 10k ohms resistor, because it dimmed the LED background light way to much and after adjusting the potentiometer to about 1,64k ohms the visibility of desired output was optimal.